An example of a known refrigeration machine for refrigerating and freezing purposes (refrigeration apparatus) being a refrigeration cycle apparatus includes a fundamental refrigerant circuit in which a compressor, condenser, expansion valve, and evaporator are connected in sequence by pipes. It may have a configuration that further includes a subcooling device disposed between the condenser and expansion valve. In that configuration, the refrigerant is further cooled from a saturated liquid to subcooled state, thereby increasing an enthalpy difference in the evaporator, enhancing the capability, and improving the performance or the like. Examples of the means for subcooling the refrigerant may include an air heat exchanger that causes heat exchange between the air and refrigerant and a refrigerant-refrigerant heat exchanger that causes heat exchange between refrigerants. There is a refrigeration cycle apparatus including a refrigerant circuit having these heat exchangers (see, for example, Patent Literatures 1 and 2).